Aeolus Introduction

ADM-Aeolus is the second of ESA’s Earth Explorer core missions. The mission's objective is to provide profiles of high-quality wind observations from the surface to 30 km, using a Doppler wind lidar (DWL) instrument (known as ALADIN) in a near-polar sun-synchronous, dawn-dusk orbit. The wind information is the horizontal line-of-sight component, in the direction perpendicular to the satellite's velocity. The mission is intended to have a minimum lifetime of three years.

ECMWF is contracted by ESA to develop (in close collaboration with KNMI) the Aeolus Level 2B/C processing software i.e. the wind retrieval.  The L2B wind retrieval algorithms have also been developed in the past in collaboration with Météo-France, DLR and LMD/IPSL.  ECMWF will also generate the L2B products operationally at ECMWF, and provide the products to ESA for further distribution.  ECMWF intend to assimilate the L2B winds in ECMWF's global NWP model if positive impact on forecast skill can be demonstrated. Aeolus will also provide information on the atmosphere's cloud and aerosol optical properties (via the L2A product).  Since ALADIN is a High Spectral Resolution Lidar; the L2A product may be useful for atmospheric composition modelling.  ECMWF has contributed to ESA funded data impact studies to assess the potential impact of the Aeolus data over the years. We expect the Aeolus mission to have a positive impact on analysis and forecast quality, in particular the improvement of analysis winds in the tropics which should lead to useful improvements.

More information on Aeolus can be found at ESA's website.

The L2B processing software

ECMWF and KNMI develop the ADM-Aeolus Level-2B wind retrieval software which produces Horizontal Line of Sight (HLOS) winds suitable for use in NWP and meteorological research.  The algorithms are described in Tan et al. (Tellus, A, 2008, 60, 2, 191-205), however note that there have been many modifications to the software since the reference was written.

Downloading the L2B processing software

• The ADM-Aeolus Level-2B/C processing documentation (including the Software Release Note, the Algorithm Theoretical Baseline and the Input/Output Data Definitions Interface Control documents) and associated datasets (needed to test the success of the installation) can be freely downloaded from here
• The source code can be downloaded for free from from our website (upon acceptance of the licence terms) 
• Any news on updates to the software, e.g. new deliveries, will be provided here
• Technical Notes prepared for ESA which are related to the L2B/C processing can be downloaded here (they are useful to help understand more about the L2B products)